1. Field of the Invention
The present invention relates to a process for producing phenoxycarboxylic acid derivatives useful as agricultural chemicals.
2. Description of the Prior Arts
It has been known that phenoxycarboxylic acid derivatives can be produced by reacting a phenol compound having the formula ##STR5## wherein R represents ##STR6## and X.sub.1 represents a hydrogen atom, a halogen atom, a lower alkyl group, trifluoromethyl group, nitro group or cyano group; X.sub.2 represents a hydrogen atom, a halogen atom, a lower alkyl group, nitro group or cyano group, with a halogen compound having the formula EQU X--R'
wherein R' represents ##STR7## and R.sub.1 and R.sub.2 respectively represent a hydrogen atom or a lower alkyl group and X represents a halogen atom, in a solvent such as ketones e.g. acetone, butanone and methyl ethyl ketone; ethers e.g. tetrahydrofuran, diethyl ether, methyl butyl ether, ethyleneglycol dimethyl ether; dimethylformamide, dimethylacetamide, dimethylsulfoxide, benzene, toluene and hexane, in the presence of a dehydrogenhalide agent of an alkali metal compound such as sodium or potassium compound or an alkaline earth metal compound such as calcium or magnesium compound. This is disclosed in Japanese Unexamined Patent Publication No. 22432/1973, 125228/1976, 32730/1976, and 87173/1977.
However, a dehydrogenhalidation of the halogen compound is caused by this process. Thus, a large amount of the halogen compound should be used and a large amount of the by-products is produced to cause low yield of the object compound.
The inventors have studied to obtain a phenoxycarboxylic acid derivative having high purity in high yield.